It is known in the art relating to internal combustion engines having cylinders with poppet intake valves to provide intake ports of a straight non-swirl type. Alternatively, there may be provided so called "swirl ports" in which the configuration of the passage defined by an intake port causes a significant degree of swirl to be generated in the charge flow entering the cylinder past the intake valve. In some instances, divided flow intake ports have been proposed in which movable valves or vanes vary the flow path within the port and control the amount of swirl generated by the port during the cylinder intake stroke.
In general such variable swirl ports require the provision of mechanical actuating devices within the port. These may involve complicated controls or actuating systems which interfere to some extent with free flow through the port under unthrottled conditions when swirl may not be required. Likewise, non-adjustable swirl ports, in general, are configured in a manner that interferes with the free breathing or maximum flow of the ports under conditions where swirl is not required in the engine cylinders.
The prior art pertaining to fluid flow in general also includes so called fluidic valves or control devices in which the rate of flow through a passage is varied by the use of a lateral control port which deflects the natural direction of flow of fluid into a swirling pattern in a vortex chamber. This is conventionally used to control the rate or direction of flow of a main fluid stream through the application of a smaller control stream, or pressure, of fluid from an external source. It is believed that the application of this technology to the control of fluid flow in engine intake ports has not been previously proposed or its capabilities appreciated.